Abe George

July 1955. Six juveniles, including Minakami Mario, who were considered to be heinous criminals, were sent to the Shounan Special Reformatory. After being treated like insects by the instructor and undergoing a humiliating physical examination, they were placed in a room called "Block 2, Cell 6." In the midst of repeated fights and abuse, they face absurdity and live strongly under the teachings of their senior cellmate Sakuragi Rokurouta (a.k.a. "Bro").

Seventeen years ago, a baby boy was abandoned in front of the daycare center. In his small hand was an old die with a tiger sitting on the second dot. It was a mysterious ivory die made with prayers in ancient India. Now a high school student, Sho works at the "Niko Niko Garden" daycare center after school. One day, a small problem occurred at Niko Niko Garden. The mother of Shin-chan, a child attending kindergarten, hasn't come to pick him up. Apparently, his father has become addicted to gambling, and his mother is working hard to pay it off. The gambling is Chinchirorin, a dice game. When Choji hears about it from his granddaughter Minako, he worries, "That's not a game for decent people"